Shield master rework by SoapingLance

You use shields not just for protection but also for offense. You gain the following benefits while you are wielding a shield:

• If you take the Attack action on your turn, you gain an additional shield attack (1d2+str/dex) you can only make one shield attack per turn. (Note that these attacks do not stack with the revised dual wielder feat, you must use one or the other during your turn. You can however use divine smite with these extra attacks.)

• If you aren't incapacitated, you can add your shield's AC bonus to any Dexterity saving throw you make against a spell or other harmful effect that targets only you.

• As a reaction on an enemies turn, if they target one of your allies that is 5 feet away from you, you can spend your reaction to add your shields bonus AC to your ally until your next turn, if you do this all enemy attack rolls have advantage against you until your next turn.